Lyophilized, spray-dried, or solid medicines that are injected generally require dissolution into a liquid in order to be injected. This process of mixing a solid with a liquid to produce an injectable form of a medication is commonly termed reconstitution. Reconstitution may also refer to mixing of any combination of liquids, solids, and gas components, whether pharmaceutically active, an expedient, or an inert carrier material. Approximately one third of all injected medicines are reconstituted prior to use. These medicines include, but are not limited to, vaccines, basic materials, acidic materials, diluents, buffers, proteins, peptides, monoclonal antibodies, antibodies, fragments of biological material, antigens, organics, inorganics, DNA, RNA, liposomes, nanoparticles, small molecules, large molecules, atomic or molecular materials, combinations of any of these, and many other substances and combinations.
The two main drawbacks of current techniques for reconstitution of injectable medications are that they are either difficult to use, expensive and/or cumbersome to manufacture, or both. Some reconstitution systems contain a bypass channel within the wall of the cartridge or syringe housing that allows liquid to flow through from one compartment to another. This requires a custom piece of glass or plastic in the form of a cartridge or syringe, which is typically expensive and difficult to produce. Additionally, the rubber component used to separate dry and liquid materials in the two compartments of such a bypass syringe are often prone to slipping when force is applied in one chamber. This slippage may cause premature leakage around the rubber component and/or the bypass.
Therefore, although a variety of reconstitution devices have been developed, improvements would still be desirable. Ideally, an improved reconstitution device would provide consistent and reliable separation of a two different substances in two separate compartments of a cartridge or syringe, with very little tendency for leakage from one compartment to the other or unwanted slipping of the reconstitution device. Also ideally, such a reconstitution device would be relatively easy and inexpensive to manufacture. At least some of these objectives will be met by the embodiments described herein.